The present invention is directed to a device to prevent oil from xe2x80x9cinadvertentlyxe2x80x9d draining from the oil pan. More particularly, the present invention is directed to a combined sealing washer and a tamper evident cap for enclosing the drain plug.
Following an oil change, a vehicle""s drain plug will occasionally not be fully seated and will vibrate loose, resulting in the oil draining out of the crank case (or oil pan) and the engine overheating, seizing or otherwise being severely damaged. A recent scam being employed by some unscrupulous persons is to take a xe2x80x9cclunkerxe2x80x9d to a local outlet of a nationwide chain of service centers, having the oil changed, intentionally backing the plug out a few rotations, knowing that after a few hundred miles, the plug will work its way out of threaded engagement in the oil pan. The oil xe2x80x9cinadvertentlyxe2x80x9d drains out, resulting in a blown engine that is then replaced by the nationwide chain to avoid the bad publicity of a dissatisfied customer. This results in a significant cost to the service center which necessarily is passed on to the consumer in the form of increased costs of service.
The present invention is designed to keep the oil plug in threaded engagement with the oil pan and to prevent anyone from backing the plug out to perpetrate such a fraud on a service center. The sealing device is comprised of a elastomeric washer that seats under the head of the bolt serving as the oil plug; a cylindrical sleeve extending up from the washer and integral therewith, the cylindrical sleeve having securement means adjacent an upper edge thereof, a tamper-resistant, tamper-evident cap attachable to the cylindrical sleeve by said securement means, the cap surrounding the head portion of the oil plug preventing access thereto, attempted removal of the cap resulting in damage to said apparatus which makes such an attempt apparent; whereby the sealing device prevents loosening of the oil plug until it is intentionally removed. The device further comprises a membrane extending between the washer and the cap whereby said apparatus forms a single integral unit. The integral unit is preferably made of a single elastomeric material such as polypropylene. The device includes a thin-walled region of at least one of the cylindrical wall and the cap whereby attempted removal of the apparatus will result in the apparatus being rendered unusable. It will be impossible to loosen the bolt and reengage the cap to make it appear as if the installer was at fault. Further, the device is sized such that when the cap is secure, even were the oil plug to loosen, it would nonetheless remain in threaded engagement with the oil pan. In on embodiment, even if the cap is pried off, the washer will remain in sealing engagement beneath the bolt head maintaining the oil plug fully seated until it is intentionally removed to permit the oil to be drained. In a second embodiment, the prying off of the cap results in the cap being torn so that the oil cap cannot be reengaged. This prevents the oil plug from being tampered with and the cap reinstalled to make it appear that an error was made by the professional at the service center. In addition, these weakened areas of the cylindrical wall and the cap facilitate removal prior to a subsequent oil change.
Various other features, advantages and characteristics of the present invention will become apparent after a reading of the following specification.